U.S. patent application number 12/241405 was filed with the patent office on 2009-06-04 for medium access control header format.
This patent application is currently assigned to QUALCOMM Incorporated. Invention is credited to Sai Yiu Duncan Ho.
Application Number | 20090141670 12/241405 |
Document ID | / |
Family ID | 40475877 |
Filed Date | 2009-06-04 |
United States Patent
Application |
20090141670 |
Kind Code |
A1 |
Duncan Ho; Sai Yiu |
June 4, 2009 |
MEDIUM ACCESS CONTROL HEADER FORMAT
Abstract
Systems and methodologies are described that facilitate
employing a variety of medium access control (MAC) header formats
in wireless communications. The MAC header formats can be
specialized for a particular type of data included in a protocol
data unit (PDU). In addition, the MAC headers can have a variable
length to accommodate payloads of varying sizes without incurring
unnecessary overhead. Further, mechanisms are provided to enable
direct access and delivery of control PDUs to associated protocol
layers to ensure better quality of service treatment.
Inventors: |
Duncan Ho; Sai Yiu; (San
Diego, CA) |
Correspondence
Address: |
QUALCOMM INCORPORATED
5775 MOREHOUSE DR.
SAN DIEGO
CA
92121
US
|
Assignee: |
QUALCOMM Incorporated
San Diego
CA
|
Family ID: |
40475877 |
Appl. No.: |
12/241405 |
Filed: |
September 30, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60976764 |
Oct 1, 2007 |
|
|
|
Current U.S.
Class: |
370/328 |
Current CPC
Class: |
H04L 2012/6448 20130101;
H04W 80/02 20130101; H04W 28/06 20130101; H04W 28/065 20130101;
H04L 69/22 20130101; H04L 29/0653 20130101 |
Class at
Publication: |
370/328 |
International
Class: |
H04W 4/00 20090101
H04W004/00 |
Claims
1. A method that facilitates employing a plurality of medium access
control header formats, comprising: determining type of data
included in an associated medium access control protocol data unit;
generating a medium access control header in accordance with a
header format that corresponds to the determined type of data; and
transmitting the medium access control header and the associated
protocol data unit.
2. The method of claim 1, the type of data includes at least one of
control data, user data or pad data.
3. The method of claim 1, the header format includes at least one
of a control header, a user header or a pad header.
4. The method of claim 3, the control header comprises a logical
channel identifier, a protocol identifier, a medium access control
length, and a second level logical channel identifier.
5. The method of claim 4, the protocol identifier specifies a
protocol layer associated with a protocol data unit encapsulated in
the medium access control protocol data unit.
6. The method of claim 5, the protocol identifier specifies at
least of a medium access control protocol data unit, a radio link
control protocol data unit or a packet data convergence protocol
data unit.
7. The method of claim 3, the user header comprises a logical
channel identifier, a medium access control length, and a size of
medium access control length.
8. The method of claim 7, wherein the medium access control length
is variable.
9. The method of claim 8, the medium access control length
comprises at least one of zero bits, seven bits, or fifteen
bits.
10. The method of claim 3, the pad header comprises a logical
channel identifier and a reserved field.
11. A communications apparatus that facilitates utilizing variable
medium access control headers, comprising: means for determining
type of data included in an associated protocol data unit; means
for generating a medium access control header in accordance with a
header format that corresponds to the determined type of data; and
means for means for transmitting the medium access control header
and the associated protocol data unit.
12. The communications apparatus of claim 11, wherein the type of
data includes at least one of control data, user data or pad
data.
13. The communications apparatus of claim 11, wherein the header
format includes at least one of a control header, a user header or
a pad header.
14. The communications apparatus of claim 13, wherein the control
header comprises a logical channel identifier, a protocol
identifier, a medium access control length, and a second level
logical channel identifier.
15. The communications apparatus of claim 14, wherein the protocol
identifier specifies a protocol layer associated with a protocol
data unit encapsulated in the medium access control protocol data
unit.
16. The communications apparatus of claim 15, wherein the protocol
identifier specifies at least of a medium access control protocol
data unit, a radio link control protocol data unit or a packet data
convergence protocol data unit.
17. The communications apparatus of claim 13, wherein the user
header comprises a logical channel identifier, a medium access
control length, and a size of medium access control length.
18. The communications apparatus of claim 17, wherein the medium
access control length is variable.
19. The communications apparatus of claim 18, wherein the medium
access control length comprises at least one of zero bits, seven
bits, or fifteen bits.
20. The communications apparatus of claim 13, wherein the pad
header comprises a logical channel identifier and a reserved
field.
21. A wireless communications apparatus, comprising: a memory that
retains instructions related to determining type of data included
in an associated medium access control protocol data unit wherein
the type of data includes at least one of control data, user data
or pad data, generating a medium access control header in
accordance with a header format that corresponds to the determined
type of data and transmitting the medium access control header and
the associated protocol data unit; and a processor, coupled to the
memory, configured to execute the instructions retained in the
memory.
22. A computer program product, comprising: a computer-readable
medium comprising: code for causing at least one computer to
determine type of data included in an associated medium access
control protocol data unit wherein the type of data includes at
least one of control data, user data or pad data; code for causing
at least one computer to generate a medium access control header in
accordance with a header format that corresponds to the determined
type of data; and code for causing at least one computer to
transmit the medium access control header and the associated
protocol data unit.
23. A method that facilitates communicating with variable medium
access control header formats, comprising: receiving a medium
access control protocol data unit and an associated header;
determining a type of data included the packet data unit based at
least in part on a logical channel identifier in the associated
header; and evaluating the medium access control protocol data unit
in accordance with the type of data and one or more protocol
layers.
24. The method of claim 23, wherein the type of data includes at
least one of a control data, user data or pad data.
25. The method of claim 24, further comprising ascertaining a
protocol layer associated with an encapsulated control data unit
for control data based at least in part on a protocol identifier
included in a control data medium access control header.
26. The method of claim 25, further comprising directly delivering
the encapsulated control data to the associated protocol layer.
27. The method of claim 24, further comprising determining size of
a length field in the associated header based at least in part on a
size of length field.
28. A communications apparatus that facilitates communicating with
variable medium access control header formats, comprising: means
for receiving a medium access control protocol data unit and an
associated header; means for determining a type of data included
the packet data unit based at least in part on a logical channel
identifier in the associated header; and means for evaluating the
medium access control protocol data unit in accordance with the
type of data and one or more protocol layers.
29. The communications apparatus of claim 28, wherein the type of
data includes at least one of a control data, user data or pad
data.
30. The communications apparatus of claim 29, further comprising
means for ascertaining a protocol layer associated with an
encapsulated control data unit for control data based at least in
part on a protocol identifier included in a control data medium
access control header.
31. The communications apparatus of claim 30, further comprising
means for directly delivering the encapsulated control data to the
associated protocol layer.
32. The communications apparatus of claim 28, further comprising
determining size of a length field in the associated header based
at least in part on a size of length field.
33. A wireless communications apparatus, comprising: a memory that
retains instructions related to receiving a medium access control
protocol data unit and an associated header, determining a type of
data included the packet data unit based at least in part on a
logical channel identifier in the associated header wherein the
type of data can be at least one of control data, user data or pad
data and evaluating the medium access control protocol data unit in
accordance with the type of data and one or more protocol layers;
and a processor, coupled to the memory, configured to execute the
instructions retained in the memory.
34. A computer program product, comprising: a computer-readable
medium comprising: code for causing at least one computer to
receive a medium access control protocol data unit and an
associated header; code for causing at least one computer to
determine a type of data included the packet data unit based at
least in part on a logical channel identifier in the associated
header wherein the type of data can be at least one of control
data, user data or pad data; and code for causing at least one
computer to evaluate the medium access control protocol data unit
in accordance with the type of data and one or more protocol
layers.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent application Ser. No. 60/976,764 entitled "LONG TERM
EVOLUTION MAC HEADER FORMAT OPTIMIZED DESIGN" which was filed Oct.
1, 2007. The entirety of the aforementioned application is herein
incorporated by reference.
BACKGROUND
[0002] I. Field
[0003] The following description relates generally to wireless
communications, and more particularly to an optimized design of a
medium access control header format.
[0004] II. Background
[0005] Wireless communication systems are widely deployed to
provide various types of communication content such as, for
example, voice, data, and so on. Typical wireless communication
systems may be multiple-access systems capable of supporting
communication with multiple users by sharing available system
resources (e.g., bandwidth, transmit power, . . . ). Examples of
such multiple-access systems may include code division multiple
access (CDMA) systems, time division multiple access (TDMA)
systems, frequency division multiple access (FDMA) systems,
orthogonal frequency division multiple access (OFDMA) systems, and
the like. Additionally, the systems can conform to specifications
such as third generation partnership project (3GPP), 3GPP2, 3GPP
long-term evolution (LTE), etc.
[0006] Generally, wireless multiple-access communication systems
may simultaneously support communication for multiple mobile
devices. Each mobile device may communicate with one or more base
stations via transmissions on forward and reverse links. The
forward link (or downlink) refers to the communication link from
base stations to mobile devices, and the reverse link (or uplink)
refers to the communication link from mobile devices to base
stations. Further, communications between mobile devices and base
stations may be established via single-input single-output (SISO)
systems, multiple-input single-output (MISO) systems,
multiple-input multiple-output (MIMO) systems, and so forth. In
addition, mobile devices can communicate with other mobile devices
(and/or base stations with other base stations) in peer-to-peer
wireless network configurations.
[0007] Wireless communication systems oftentimes employ one or more
base stations that provide a coverage area. A typical base station
can transmit multiple data streams for broadcast, multicast and/or
unicast services, wherein a data stream may be a stream of data
that can be of independent reception interest to an access
terminal. An access terminal within the coverage area of such base
station can be employed to receive one, more than one, or all the
data streams carried by the composite stream. Likewise, an access
terminal can transmit data to the base station or another access
terminal.
[0008] MIMO systems commonly employ multiple (N.sub.T) transmit
antennas and multiple (N.sub.R) receive antennas for data
transmission. A MIMO channel formed by the N.sub.T transmit and
N.sub.R receive antennas may be decomposed into N.sub.S independent
channels, which may be referred to as spatial channels, where
N.sub.S.ltoreq.{N.sub.T, N.sub.R}. Each of the Ns independent
channels corresponds to a dimension. Moreover, MIMO systems may
provide improved performance (e.g., increased spectral efficiency,
higher throughput and/or greater reliability) if the additional
dimensionalities created by the multiple transmit and received
antennas are utilized.
SUMMARY
[0009] The following presents a simplified summary of one or more
embodiments in order to provide a basic understanding of such
embodiments. This summary is not an extensive overview of all
contemplated embodiments, and is intended to neither identify key
or critical elements of all embodiments nor delineate the scope of
any or all embodiments. Its sole purpose is to present some
concepts of one or more embodiments in a simplified form as a
prelude to the more detailed description that is presented
later.
[0010] In accordance with one or more embodiments and corresponding
disclosure thereof, various aspects are described in connection
with utilizing a plurality of medium access control (MAC) header
formats in wireless communications The MAC header formats can be
specialized for a particular type of data included in a protocol
data unit (PDU). In addition, the MAC headers can have a variable
length to accommodate payloads of varying sizes without incurring
unnecessary overhead. Further, mechanisms are provided to enable
direct access and delivery of control PDUs to associated protocol
layers to ensure better quality of service treatment.
[0011] According to related aspects, a method that facilitates
employing a plurality of medium access control header formats is
provided. The method can comprise determining type of data included
in an associated medium access control protocol data unit. The
method can also include generating a medium access control header
in accordance with a header format that corresponds to the
determined type of data. In addition, the method can comprise
transmitting the medium access control header and the associated
protocol data unit.
[0012] Another aspect relates to a communications apparatus that
facilitates utilizing variable medium access control headers. The
communications apparatus can include means for determining type of
data included in an associated protocol data unit. The
communications apparatus can also comprise means for generating a
medium access control header in accordance with a header format
that corresponds to the determined type of data. In addition, the
communications apparatus can include means for means for
transmitting the medium access control header and the associated
protocol data unit.
[0013] Yet another aspect relates to a wireless communications
apparatus. The wireless communications apparatus can include a
memory a memory that retains instructions related to determining
type of data included in an associated medium access control
protocol data unit wherein the type of data includes at least one
of control data, user data or pad data, generating a medium access
control header in accordance with a header format that corresponds
to the determined type of data and transmitting the medium access
control header and the associated protocol data unit. In addition,
the wireless communications apparatus can further comprise a
processor, coupled to the memory, configured to execute the
instructions retained in the memory.
[0014] Still another aspect relates to a computer program product,
which can have a computer-readable medium. The computer-readable
medium can include code for causing at least one computer to
determine type of data included in an associated medium access
control protocol data unit wherein the type of data includes at
least one of control data, user data or pad data. The
computer-readable medium can also comprise code for causing at
least one computer to generate a medium access control header in
accordance with a header format that corresponds to the determined
type of data. In addition, the computer-readable medium can include
code for causing at least one computer to transmit the medium
access control header and the associated protocol data unit.
[0015] Another aspect described herein relates to a method that
facilitates communicating with variable medium access control
header formats. The method can include receiving a medium access
control protocol data unit and an associated header. The method can
also comprise determining a type of data included the packet data
unit based at least in part on a logical channel identifier in the
associated header. In addition, the method can include evaluating
the medium access control protocol data unit in accordance with the
type of data and one or more protocol layers.
[0016] Still yet another aspect relates to a communications
apparatus that facilitates communicating with variable medium
access control header formats. The communications apparatus can
include means for receiving a medium access control protocol data
unit and an associated header. The communications apparatus can
also comprise means for determining a type of data included the
packet data unit based at least in part on a logical channel
identifier in the associated header. In addition, the
communications apparatus can include means for evaluating the
medium access control protocol data unit in accordance with the
type of data and one or more protocol layers.
[0017] A further aspect described herein relates to a wireless
communications apparatus that can comprise a memory. The memory can
retain instructions related to receiving a medium access control
protocol data unit and an associated header, determining a type of
data included the packet data unit based at least in part on a
logical channel identifier in the associated header wherein the
type of data can be at least one of control data, user data or pad
data and evaluating the medium access control protocol data unit in
accordance with the type of data and one or more protocol layers.
In addition, the wireless communications apparatus can also include
a processor, coupled to the memory, configured to execute the
instructions retained in the memory.
[0018] Still another aspect relates to a computer program product,
which can have a computer-readable medium that includes code for
causing at least one computer to receive a medium access control
protocol data unit and an associated header. The computer-readable
medium can also comprise code for causing at least one computer to
determine a type of data included the packet data unit based at
least in part on a logical channel identifier in the associated
header wherein the type of data can be at least one of control
data, user data or pad data. In addition, the computer-readable
medium can include code for causing at least one computer to
evaluate the medium access control protocol data unit in accordance
with the type of data and one or more protocol layers.
[0019] To the accomplishment of the foregoing and related ends, the
one or more embodiments comprise the features hereinafter fully
described and particularly pointed out in the claims. The following
description and the annexed drawings set forth in detail certain
illustrative aspects of the one or more embodiments. These aspects
are indicative, however, of but a few of the various ways in which
the principles of various embodiments may be employed and the
described embodiments are intended to include all such aspects and
their equivalents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 is an illustration of a wireless communication system
in accordance with various aspects set forth herein.
[0021] FIG. 2 is an illustration of an example communications
apparatus for employment within a wireless communications
environment.
[0022] FIG. 3 is an illustration of an example wireless
communications system that facilitates employing a variety of MAC
header formats that can include variable lengths.
[0023] FIG. 4 is an illustration of example MAC header formats in
accordance with an aspect of the subject disclosure.
[0024] FIG. 5 is an illustration of an example methodology that
facilitates selecting and generating a MAC header in accordance
with an aspect of the subject disclosure.
[0025] FIG. 6 is an illustration of an example methodology that
facilitates that facilitates receiving MAC headers in accordance
with an aspect.
[0026] FIG. 7 is an illustration of an example system that
facilitates employing a variety of medium access control (MAC)
headers in accordance with an aspect of the subject disclosure.
[0027] FIG. 8 is an illustration of an example system that
facilitates communications associated with a mobile device in a
wireless communication system in accordance with an aspect of the
disclosed subject matter
[0028] FIG. 9 is an illustration of an example wireless network
environment that can be employed in conjunction with the various
systems and methods described herein.
[0029] FIG. 10 is an illustration of an example system that
determines a header format to employ in transmitting data in a
wireless communication system.
[0030] FIG. 11 is an illustration of an example system that
facilitates receiving transmissions that include variable medium
access control header formats.
DETAILED DESCRIPTION
[0031] Various embodiments are now described with reference to the
drawings, wherein like reference numerals are used to refer to like
elements throughout. In the following description, for purposes of
explanation, numerous specific details are set forth in order to
provide a thorough understanding of one or more embodiments. It may
be evident, however, that such embodiment(s) can be practiced
without these specific details. In other instances, well-known
structures and devices are shown in block diagram form in order to
facilitate describing one or more embodiments.
[0032] As used in this application, the terms "component,"
"module," "system," and the like are intended to refer to a
computer-related entity, either hardware, firmware, a combination
of hardware and software, software, or software in execution. For
example, a component can be, but is not limited to being, a process
running on a processor, a processor, an object, an executable, a
thread of execution, a program, and/or a computer. By way of
illustration, both an application running on a computing device and
the computing device can be a component. One or more components can
reside within a process and/or thread of execution and a component
can be localized on one computer and/or distributed between two or
more computers. In addition, these components can execute from
various computer readable media having various data structures
stored thereon. The components can communicate by way of local
and/or remote processes such as in accordance with a signal having
one or more data packets (e.g., data from one component interacting
with another component in a local system, distributed system,
and/or across a network such as the Internet with other systems by
way of the signal).
[0033] Furthermore, various embodiments are described herein in
connection with a mobile device. A mobile device can also be called
a system, subscriber unit, subscriber station, mobile station,
mobile, remote station, remote terminal, access terminal, user
terminal, terminal, wireless communication device, user agent, user
device, or user equipment (UE). A mobile device can be a cellular
telephone, a cordless telephone, a Session Initiation Protocol
(SIP) phone, a wireless local loop (WLL) station, a personal
digital assistant (PDA), a handheld device having wireless
connection capability, computing device, or other processing device
connected to a wireless modem. Moreover, various embodiments are
described herein in connection with a base station. A base station
can be utilized for communicating with mobile device(s) and can
also be referred to as an access point, Node B, evolved Node B
(eNode B or eNB), base transceiver station (BTS) or some other
terminology.
[0034] Moreover, various aspects or features described herein can
be implemented as a method, apparatus, or article of manufacture
using standard programming and/or engineering techniques. The term
"article of manufacture" as used herein is intended to encompass a
computer program accessible from any computer-readable device,
carrier, or media. For example, computer-readable media can include
but are not limited to magnetic storage devices (e.g., hard disk,
floppy disk, magnetic strips, etc.), optical disks (e.g., compact
disk (CD), digital versatile disk (DVD), etc.), smart cards, and
flash memory devices (e.g., EPROM, card, stick, key drive, etc.).
Additionally, various storage media described herein can represent
one or more devices and/or other machine-readable media for storing
information. The term "machine-readable medium" can include,
without being limited to, wireless channels and various other media
capable of storing, containing, and/or carrying instruction(s)
and/or data.
[0035] The techniques described herein may be used for various
wireless communication systems such as code division multiple
access (CDMA), time division multiple access (TDMA), frequency
division multiple access (FDMA), orthogonal frequency division
multiple access (OFDMA), single carrier frequency domain
multiplexing (SC-FDMA) and other systems. The terms "system" and
"network" are often used interchangeably. A CDMA system may
implement a radio technology such as Universal Terrestrial Radio
Access (UTRA), CDMA2000, etc. UTRA includes Wideband-CDMA (W-CDMA)
and other variants of CDMA. CDMA2000 covers IS-2000, IS-95 and
IS-856 standards. A TDMA system may implement a radio technology
such as Global System for Mobile Communications (GSM). An OFDMA
system may implement a radio technology such as Evolved UTRA
(E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE
802.16 (WiMAX), IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are
part of Universal Mobile Telecommunication System (UMTS). 3GPP Long
Term Evolution (LTE) is an upcoming release of UMTS that uses
E-UTRA, which employs OFDMA on the downlink and SC-FDMA on the
uplink. UTRA, E-UTRA, UMTS, LTE and GSM are described in documents
from an organization named "3rd Generation Partnership Project"
(3GPP). CDMA2000 and UMB are described in documents from an
organization named "3rd Generation Partnership Project 2"
(3GPP2).
[0036] Referring now to FIG. 1, a wireless communication system 100
is illustrated in accordance with various embodiments presented
herein. System 100 comprises a base station 102 that can include
multiple antenna groups. For example, one antenna group can include
antennas 104 and 106, another group can comprise antennas 108 and
110, and an additional group can include antennas 112 and 114. Two
antennas are illustrated for each antenna group; however, more or
fewer antennas can be utilized for each group. Base station 102 can
additionally include a transmitter chain and a receiver chain, each
of which can in turn comprise a plurality of components associated
with signal transmission and reception (e.g., processors,
modulators, multiplexers, demodulators, demultiplexers, antennas,
etc.), as will be appreciated by one skilled in the art.
[0037] Base station 102 can communicate with one or more mobile
devices such as mobile device 116 and mobile device 122; however,
it is to be appreciated that base station 102 can communicate with
substantially any number of mobile devices similar to mobile
devices 116 and 122. Mobile devices 116 and 122 can be, for
example, cellular phones, smart phones, laptops, handheld
communication devices, handheld computing devices, satellite
radios, global positioning systems, PDAs, and/or any other suitable
device for communicating over wireless communication system 100. As
depicted, mobile device 116 is in communication with antennas 112
and 114, where antennas 112 and 114 transmit information to mobile
device 116 over a forward link 118 and receive information from
mobile device 116 over a reverse link 120. Moreover, mobile device
122 is in communication with antennas 104 and 106, where antennas
104 and 106 transmit information to mobile device 122 over a
forward link 124 and receive information from mobile device 122
over a reverse link 126. In a frequency division duplex (FDD)
system, forward link 118 can utilize a different frequency band
than that used by reverse link 120, and forward link 124 can employ
a different frequency band than that employed by reverse link 126,
for example. Further, in a time division duplex (TDD) system,
forward link 118 and reverse link 120 can utilize a common
frequency band and forward link 124 and reverse link 126 can
utilize a common frequency band.
[0038] Each group of antennas and/or the area in which they are
designated to communicate can be referred to as a sector of base
station 102. For example, antenna groups can be designed to
communicate to mobile devices in a sector of the areas covered by
base station 102. In communication over forward links 118 and 124,
the transmitting antennas of base station 102 can utilize
beamforming to improve signal-to-noise ratio of forward links 118
and 124 for mobile devices 116 and 122. This can be provided by
using a precoder to steer signals in desired directions, for
example. Also, while base station 102 utilizes beamforming to
transmit to mobile devices 116 and 122 scattered randomly through
an associated coverage, mobile devices in neighboring cells can be
subject to less interference as compared to a base station
transmitting through a single antenna to all its mobile devices.
Moreover, mobile devices 116 and 122 can communicate directly with
one another using a peer-to-peer or ad hoc technology in one
example. According to an example, system 100 can be a
multiple-input multiple-output (MIMO) communication system.
Further, system 100 can utilize substantially any type of duplexing
technique to divide communication channels (e.g., forward link,
reverse link, . . . ) such as FDD, TDD, and the like.
[0039] Turning to FIG. 2, illustrated is a communications apparatus
200 for employment within a wireless communications environment.
The communications apparatus 200 can be a base station or a portion
thereof, a mobile device or a portion thereof, or substantially any
communications apparatus that receives data transmitted in a
wireless communications environment. In communications systems, the
communications apparatus 200 can employ components described below
to enable variable medium access control header formats to be
utilized.
[0040] The communications apparatus 200 can leverage protocols
associated with a variety of protocol layers for communication. For
instance, the communications apparatus 200 can a radio resource
control (RRC) module 202 that can provide RRC protocol
functionality. For example, the RRC module 202 can facilitate
control plane signaling between mobile devices, base stations and a
communications network. In addition, the RRC module 202 can perform
configurational and operational operations such as, connection
establishment and release, system information broadcast, bearer
establishment, reconfiguration and release, connection mobility
procedures, paging notification, power control, etc. The
communications apparatus 200 also can include a packet data
convergence (PDCP) module 204 that can manage the PDCP layer in
wireless communications. For example, the PDCP module 204 can
perform IP header compression and decompression, user data
transfer, maintenance of sequence numbers for radio bearers and the
like. Moreover, the communications apparatus 200 can further
include a radio link control (RLC) module 206 that provides RLC
protocol functionality. The communications apparatus can also
include a medium access control (MAC) module 208 that can
facilitate access to a shared medium. In addition, the
communications apparatus 200 can include a physical layer module
210 that can manage and control the radio interface employed to
transmit and receive signals.
[0041] The PDCP module 204, the RLC module 202 and the MAC module
206 can generate and/or pack information into headers, packets,
payloads, protocol data units (PDUs), etc. associated with the
respective protocols. Pursuant to an example, the MAC module 206
can employ a variety of header formats depending on type of data
transmitted (e.g., user or control), size of higher layer PDUs,
purpose of the MAC PDU (e.g., pad PDU) and the like. Accordingly,
the communications apparatus 200 can include a format selector 212
that determines an appropriate MAC header format based upon
transmission needs of the communications apparatus 200. For
example, if the communications apparatus 200 transmits control
data, the format selector 212 can determine an appropriate format
for control data. The communications apparatus 200 can further
include a header encoder 214 that can generate a MAC header
according to the format selected by the format selector 212.
[0042] In one illustration, a MAC header can contain a variety of
information such, but not limited to, a logical channel identifier
(LCID) that can specify at least one of a logical channel to which
to route the MAC PDU, a length field that specifies length of the
MAC service data unit (e.g., the MAC PDU or payload), and an
extension field. In another aspect, the LCID can indicate the MAC
header format employed. In addition, a variable length field can
employed to accommodate a wide range of MAC PDU sizes. A variable
length field enables a small length field to be utilized with small
MAC PDUs and a larger length field for larger MAC PDUs, thus
minimizing unnecessary overhead. Variable length can result from
variable size PDCP or RLC PDUs encapsulated in a MAC PDU. To enable
direct delivery of upper layer control messages, the MAC header can
additionally include a field that identifies type of encapsulated
PDU (e.g., RLC or PDCP). Further, the MAC header can include
specific indicators that specify padding.
[0043] Pursuant to an illustrative embodiment, the above aspects
can be specified in a several MAC header format designs categorized
by LCID values. For instance, as described in more detail below, an
LCID value of `11111` can indicate an associated MAC PDU is
padding. In addition, an LCID value of `00000` can indicate the MAC
header is utilized with control data. Any value between `11111` and
`00000` can be reserved for user data.
[0044] Moreover, although not shown, it is to be appreciated that
communications apparatus 200 can include memory that retains
instructions associated with identifying a type of MAC header
required for a transmission, encoding the MAC header information
according to the selected format, identifying a particular MAC
format upon receipt and the like. In addition, the memory can
retain instructions for directly delivery upper layer control
message encapsulated in MAC PDUs. Further, communications apparatus
200 may include a processor that may be utilized in connection with
executing instructions (e.g., instructions retained within memory,
instructions obtained from a disparate source, . . . ).
[0045] Now referring to FIG. 3, illustrated is a wireless
communications system 300 that facilitates employing a variety of
MAC header formats that can include variable lengths. The system
300 includes a base station 302 that can communicate with user
equipment 304 (and/or any number of disparate devices (not shown)).
The base station 302 can transmit information to the user equipment
304 over a forward link channel or downlink channel; further base
station 302 can receive information from the user equipment 304
over a reverse link channel or uplink channel. Moreover, system 300
can be a MIMO system. Additionally, the system 300 can operate in
an OFDMA wireless network (such as 3GPP, 3GPP2, 3GPP LTE, etc., for
example). Also, the components and functionalities shown and
described below in the base station 302 can be present in the user
equipment 304 and vice versa, in one example.
[0046] The base station 302 can include a protocol stack, as
described above with reference to FIG. 2, with a radio resource
control (RRC) module 306, a packet data convergence protocol (PDCP)
module 308, a radio link control (RLC) module 310, a medium access
control (MAC) module 312, and a physical layer module 314. It is to
be appreciated that the base station 302 can include any suitable
number of protocol layers and the subject innovation is not limited
to the protocol layers described herein. In addition, the base
station 302 can include a format selector 316 that determines a MAC
header format to employ for a transmission from among a plurality
of formats. For instance, the format selector 316 can determine
that user data is to be transmitted and selects a format
appropriate for user data. In another example, the format selector
316 can determine that control data is to be transmitted and
chooses a control data MAC header format. In addition, the format
selector 316 can determine that a padding header format should be
employed. The base station 302 can further include a header encoder
318 that generates a MAC header in accordance with the format
selected by the format selector 316. In addition, the base station
302 can include a router 320 that can that can automatically
evaluate a received MAC header in order to communicate data to a
protocol layer within the base station 302 as defined by such MAC
header. For instance, a control data MAC header can be received
that indicates a RLC PDU is encapsulated. The router 320 can
directly deliver the RLC PDU to the RLC module 310 to provide
better quality of service treatment for the PDU.
[0047] The user equipment 304 can include a protocol stack, as
described above with reference to FIG. 2, with a radio resource
control (RRC) module 322, a packet data convergence protocol (PDCP)
module 324, a radio link control (RLC) module 326, a medium access
control (MAC) module 328, and a physical layer module 330. It is to
be appreciated that the user equipment 304 can include any suitable
number of protocol layers and the subject innovation is not limited
to the protocol layers described herein. In addition, user
equipment 304 can include a format selector 332 that determines a
MAC header format to employ for a transmission from among a
plurality of formats. For instance, the format selector 332 can
determine that user data is to be transmitted and selects a format
appropriate for user data. In another example, the format selector
332 can determine that control data is to be transmitted and
chooses a control data MAC header format. In addition, the format
selector 332 can determine that a padding header format should be
employed. The user equipment 304 can further include a header
encoder 334 that generates a MAC header in accordance with the
format selected by the format selector 332. In addition, the user
equipment 304 can include a router 336 that can that can
automatically evaluate a received MAC header in order to
communicate data to a protocol layer within the user equipment 304
as defined by such MAC header. For instance, a control data MAC
header can be received that indicates a RLC PDU is encapsulated.
The router 336 can directly deliver the RLC PDU to the RLC module
326 to provide better quality of service treatment for the PDU.
While the format selectors 316 and 332 and the header encoders 318
and 334 are shown as part of the MAC modules 312 and 328,
respectively, it is to be appreciated that the format selectors and
header encoders can be separate modules or components and/or
associated with other modules depicted in FIG. 3.
[0048] It is to be appreciated that a MAC header created by the
format selector 332 and header encoder 334 within the user
equipment 304 can be transmitted to the base station 302. The MAC
header can be evaluated by the router 320 in order to directly
transport data to a particularly defined protocol layer within the
base station 302 (e.g., thereby bypassing at least one protocol
layer above the MAC module 312). It is to be further appreciated
that a MAC header created by the format selector 316 and header
encoder 318 within the base station 302 can be communicated to the
user equipment 304. The MAC header can be evaluated by the router
336 in order to directly transport data to a particularly defined
protocol layer within the user equipment 304.
[0049] The MAC headers can include variable lengths that can
efficiently encapsulate other layer PDUs without unnecessary
overhead. The variable header format provides a plurality of
benefits. For example, a no length option is available that can be
utilized in Voice over IP (VoIP) packets that fit right into a
transport block (e.g., a block of information transmitted between
base station 302 and user equipment 304). With VoIP packets, a one
byte MAC header can suffice. Other MAC header options include a
variable length field to handle variable sized RLC PDUs on the fly.
In addition, the MAC header can include a field that allows upper
layers to access the MAC layer directly to deliver control PDUs.
Moreover, the field provides visibility of the control PDUs to a
scheduler to enable the scheduler to give those PDUs better quality
of service treatment as opposed to multiplexing control PDUs and
data PDUs on the a same radio bearer.
[0050] FIG. 4 illustrates example MAC header formats 400 in
accordance with an aspect of the subject disclosure. The formats
described herein can be selected by the format selector 212, 316
and 332 and generated by the header encoder 214, 318 and 334.
Format 402 is an exemplary format associated with control data.
Format 402 includes a logical channel identifier (LCID) value of
`00000` to identify the header as a control data header. The format
402 can further include a protocol identifier (PID) field that can
specify a protocol layer associated with an encapsulated protocol
data unit (PDU). Pursuant to an illustrative example, the PID field
can have a value of `00` to indicate an encapsulated MAC control
PDU, `01` to indicate an encapsulated RLC control PDU, and `10` to
indicate an encapsulated PDCP control PDU. It is to be appreciated
that other PID value encodings can be utilized. The format 402 can
further include two reserved fields, a 1 bit reserved field (R1)
and a three bit reserved field (R2). In addition, a bit extension
field (E) can be included. In one aspect, the E field can be
utilized to indicate additional fields are appended to the MAC
header. In format 402, a seven bit MAC length field can be included
that specifies the length of a MAC PDU payload associated with the
header. A second level LCID (LCID2) is provided in format 402 to
indicate to which logical channel to route the PDU. In one aspect,
the LCID2 field can comprise five bits of information.
[0051] Format 404 is an exemplary format that can be employed to
transmit user data. Format 404 can include a LCID field value
greater than `00000` and less than `11111` to identify the header
as a user data header. Format 404 can further include a length of
MAC length field (LM) that indicates a size of the MAC Length
field. For instance, a LM value of `00` can specify that no MAC
length field is present (e.g., length is provided by the physical
layer). A LM value of `01` can indicate a 7-bit MAC length is
included in the header followed by a 1-bit E field. A LM value of
`10` can specify a 15-bit MAC length field followed by a 1-bit E
field. The format 404 can also include a 1-bit reserved field (R1).
In FIG. 4, format 404 is depicted with a 15-bit MAC length field.
However, it is to be appreciated that other MAC lengths can be
employed as described above.
[0052] Format 406 is an exemplary format that can be utilized for
padding. Format 406 can include a LCID field value of `11111` to
identify the header as a padding header for a MAC pad PDU. To
result in an 8-bit header, a 3-bit reserved field (R1) can be
included. In one example, the R1 field is encoded with a value of
`000`.
[0053] Referring to FIGS. 5-6, methodologies relating to employing
variable length MAC header formats in wireless communications that
are designed specifically for the type of data encapsulated
therein. While, for purposes of simplicity of explanation, the
methodologies are shown and described as a series of acts, it is to
be understood and appreciated that the methodologies are not
limited by the order of acts, as some acts may, in accordance with
one or more embodiments, occur in different orders and/or
concurrently with other acts from that shown and described herein.
For example, those skilled in the art will understand and
appreciate that a methodology could alternatively be represented as
a series of interrelated states or events, such as in a state
diagram. Moreover, not all illustrated acts may be required to
implement a methodology in accordance with one or more
embodiments.
[0054] Turning to FIG. 5, illustrated is a methodology 500 that
facilitates selecting and generating a MAC header in accordance
with an aspect of the subject disclosure. In one example, the
method 500 can be employed by a base station (e.g., NodeB, evolved
NodeB, access point, . . . ) to transmit data to mobile devices
and/or by a mobile device to transmit data to a base station. At
reference numeral 502, a MAC header type is determined. For
example, the MAC header type can be a control data header, a user
data header, or a padding header. At reference numeral 504, a
decision is made as to whether the header is a user data header. If
the header is user data, the method 500 proceeds to reference
numeral 506 where a length of MAC protocol data unit is
ascertained. For instance, the size of the payload is determined.
At reference numeral 508, a size of the variable MAC length field
in the header is established. For example, the size of the MAC
length field will correlated to the length of the MAC PDU such that
a small MAC length field is established for small PDUs and a larger
MAC length field is employed with larger PDUs. Pursuant to an
illustration, the size of the variable MAC length field can be one
of no bits, 7 bits or 15 bits. At reference numeral 510, a user
data header is generated according to a MAC length field and a size
of MAC length field.
[0055] If the header is determined to not user data at 504, the
method 500 proceeds to reference numeral 512, a decision is made as
to whether the protocol data unit is a pad PDU. If yes, the method
500 proceeds to reference numeral 514 where a pad header is
generated. If no, the method 500 proceeds to reference numeral 516
where a type of control PDU to be encapsulated in the MAC PDU is
ascertained. In one example, the encapsulated control PDU can be a
MAC control PDU, a RLC control PDU or a PDCP control PDU. At
reference numeral 518, a logical channel associated with the header
is determined. For instance, the logical channel can be a channel
to which the MAC PDU is to be routed. At reference numeral 520, a
control data header is generated that include a field that
specifies the type of control PDU and a field that indicates the
logical channel.
[0056] Referring now to FIG. 6, illustrated is a methodology 600
that facilitates receiving MAC headers in accordance with an
aspect. In particular, the method 600 can be employed by a base
station and/or a mobile device to receive and process variable
length MAC headers specially designed for data type. At reference
numeral 602, a MAC PDU and header is received. At reference numeral
604, a data type associated with the MAC PDU and header is
determined. For example, the MAC PDU can be a control data PDU, a
user data PDU or a pad PDU. At reference numeral 606, a decision is
made as to whether the PDU is control data. If yes, the method 600
proceeds to reference numeral 608 where an encapsulated PDU type is
ascertained For instance, the encapsulated PDU can be a MAC control
PDU, a PDCP control PDU or a RLC control PDU. At reference numeral
510, the MAC is directly accessed and the encapsulated PDU is
directly delivered to the protocol layer associated with the
encapsulated PDU. For example, if the PDU is a PDCP PDU, the
encapsulated PDU is directly delivered to a PDPC protocol layer
module. At reference numeral 612, the MAC PDU is processed. For
example, the PDU can be processed by a MAC layer module, partially
processed by a MAC layer and passed to upper layers and/or passed
directly to upper layers.
[0057] It will be appreciated that, in accordance with one or more
aspects described herein, inferences can be made regarding
selecting an appropriate MAC header format, determining a protocol
associated with an encapsulated PDU, ascertaining a type of header,
and the like. As used herein, the term to "infer" or "inference"
refers generally to the process of reasoning about or inferring
states of the system, environment, and/or user from a set of
observations as captured via events and/or data. Inference can be
employed to identify a specific context or action, or can generate
a probability distribution over states, for example. The inference
can be probabilistic--that is, the computation of a probability
distribution over states of interest based on a consideration of
data and events. Inference can also refer to techniques employed
for composing higher-level events from a set of events and/or data.
Such inference results in the construction of new events or actions
from a set of observed events and/or stored event data, whether or
not the events are correlated in close temporal proximity, and
whether the events and data come from one or several event and data
sources.
[0058] FIG. 7 is an illustration of a mobile device 700 that
facilitates employing a variety of medium access control (MAC)
headers in accordance with an aspect of the subject disclosure. The
mobile device 700 can facilitate communications associated with a
mobile device in a wireless communication system in accordance with
an aspect of the disclosed subject matter. It is to be appreciated
that the mobile device 700 can be the same or similar as, and/or
can comprise the same or similar functionality as, mobile device
116, 122, 200, and/or 304 as more described, for example, with
regard to system 100, system 200, system 300, methodology 500, and
methodology 600.
[0059] Mobile device 700 comprises a receiver 702 that receives a
signal from, for instance, a receive antenna (not shown), performs
typical actions on (e.g., filters, amplifies, downconverts, etc.)
the received signal, and digitizes the conditioned signal to obtain
samples. Receiver 702 can be, for example, an MMSE receiver, and
can comprise a demodulator 704 that can demodulate received symbols
and provide them to a processor 706 for channel estimation.
Processor 706 can be a processor dedicated to analyzing information
received by receiver 702 and/or generating information for
transmission by a transmitter 716, a processor that controls one or
more components of mobile device 700, and/or a processor that both
analyzes information received by receiver 702, generates
information for transmission by transmitter 716, and controls one
or more components of mobile device 700. Mobile device 700 can also
comprise a modulator 714 that can work in conjunction with the
transmitter 716 to facilitate transmitting signals (e.g., data) to,
for instance, a base station (e.g., 102, 200, 302), another mobile
device (e.g., 122), etc.
[0060] Mobile device 700 can additionally comprise memory 708 that
is operatively coupled to processor 706 and that can store data to
be transmitted, received data, information related to available
channels, data associated with analyzed signal and/or interference
strength, information related to an assigned channel, power, rate,
or the like, and any other suitable information for estimating a
channel and communicating via the channel. Memory 708 can
additionally store protocols and/or algorithms associated with
estimating and/or utilizing a channel (e.g., performance based,
capacity based, etc.). Further, memory 708 can retain prioritized
bit rates, maximum bit rates, queue sizes, etc., related to one or
more bearers serviced by the mobile device 700.
[0061] It will be appreciated that the data store (e.g., memory
708) described herein can be either volatile memory or nonvolatile
memory, or can include both volatile and nonvolatile memory. By way
of illustration, and not limitation, nonvolatile memory can include
read only memory (ROM), programmable ROM (PROM), electrically
programmable ROM (EPROM), electrically erasable PROM (EEPROM), or
flash memory. Volatile memory can include random access memory
(RAM), which acts as external cache memory. By way of illustration
and not limitation, RAM is available in many forms such as
synchronous RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM
(SDRAM), double data rate SDRAM (DDR SDRAM), enhanced SDRAM
(ESDRAM), Synchlink DRAM (SLDRAM), and direct Rambus RAM (DRRAM).
The memory 708 of the subject systems and methods is intended to
comprise, without being limited to, these and any other suitable
types of memory.
[0062] Processor 706 can be operatively coupled to a MAC module 710
that can facilitate operations associated with a medium access
control protocol. In addition, the MAC module 710 can select a MAC
header format based upon type of data to be transmitted by the
mobile device 700. For instance, the MAC module 710 can employ
unique formats for control data, user data and padding. Processor
706 can further be coupled to a router 712 that can directly access
MAC layer PDUs upon receipt by the mobile device 700. The router
712 can determine if the MAC layer PDU encapsulates an upper layer
PDU and directly deliver the encapsulated PDU to the upper layer.
Mobile device 700 still further comprises a modulator 714 and
transmitter 716 that respectively modulate and transmit signals to,
for instance, a base station, another mobile device, etc. Although
depicted as being separate from the processor 706, it is to be
appreciated that the MAC module 710, router 712, demodulator 704,
and/or modulator 714 can be part of the processor 706 or multiple
processors (not shown).
[0063] FIG. 8 is an illustration of a system 800 that can
facilitate communications associated with a mobile device in a
wireless communication system in accordance with an aspect of the
disclosed subject matter. The system 800 comprises a base station
802 (e.g., access point, . . . ) with a receiver 810 that receives
signal(s) from one or more mobile devices 804 through a plurality
of receive antennas 806, and a transmitter 824 that transmits to
the one or more mobile devices 804 through a transmit antenna 808.
Receiver 810 can receive information from receive antennas 806 and
is operatively associated with a demodulator 812 that demodulates
received information. Demodulated symbols are analyzed by a
processor 814 that can that can be a processor dedicated to
analyzing information received by receiver 810, generating
information for transmission by a transmitter 824, a processor that
controls one or more components of base station 802, and/or a
processor that concurrently analyzes information received by
receiver 810, generates information for transmission by transmitter
824, and controls one or more components of base station 802. In
addition, the processor 814 can be similar to the processor
described above with regard to FIG. 6, and which is coupled to a
memory 816 that stores information related to estimating a signal
(e.g., pilot) strength and/or interference strength, data to be
transmitted to or received from mobile device(s) 804 (or a
disparate base station (not shown)), and/or any other suitable
information related to performing the various actions and functions
set forth herein.
[0064] In addition, the memory 816 can store data to be
transmitted, received data, information related to available
channels, data associated with analyzed signal and/or interference
strength, information related to an assigned channel, power, rate,
or the like, and any other suitable information for estimating a
channel and communicating via the channel. Memory 816 can
additionally store protocols and/or algorithms associated with
estimating and/or utilizing a channel (e.g., performance based,
capacity based, etc.). The base station 802 can also comprise a
modulator 822 that can work in conjunction with the transmitter 824
to facilitate transmitting signals (e.g., data) to, for instance,
mobile devices 804, another device, etc.
[0065] It will be appreciated that the memory 816 described herein
can be either volatile memory or nonvolatile memory, or can include
both volatile and nonvolatile memory. By way of illustration, and
not limitation, nonvolatile memory can include read only memory
(ROM), programmable ROM (PROM), electrically programmable ROM
(EPROM), electrically erasable PROM (EEPROM), or flash memory.
Volatile memory can include random access memory (RAM), which acts
as external cache memory. By way of illustration and not
limitation, RAM is available in many forms such as synchronous RAM
(SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data
rate SDRAM (DDR SDRAM), enhanced SDRAM (ESDRAM), Synchlink DRAM
(SLDRAM), and direct Rambus RAM (DRRAM). The memory 808 of the
subject systems and methods is intended to comprise, without being
limited to, these and any other suitable types of memory.
[0066] Processor 814 is further coupled to a MAC module 818 that
can facilitate operations associated with a medium access control
protocol. In addition, the MAC module 818 can select a MAC header
format based upon type of data to be transmitted by the base
station 802. For instance, the MAC module 818 can employ unique
formats for control data, user data and padding. Processor 814 can
further be coupled to a router 820 that can directly access MAC
layer PDUs upon receipt by the base station 802. The router 820 can
determine if the MAC layer PDU encapsulates an upper layer PDU and
directly deliver the encapsulated PDU to the upper layer.
Furthermore, although depicted as being separate from the processor
814, it is to be appreciated that the MAC module 818, router 820,
demodulator 812, and/or modulator 822 can be part of the processor
814 or multiple processors (not shown).
[0067] FIG. 9 shows an example wireless communication system 900.
The wireless communication system 900 depicts one base station 910
and one mobile device 950 for sake of brevity. However, it is to be
appreciated that system 900 can include more than one base station
and/or more than one mobile device, wherein additional base
stations and/or mobile devices can be substantially similar or
different from example base station 910 and mobile device 950
described below. In addition, it is to be appreciated that base
station 910 and/or mobile device 950 can employ the systems (FIGS.
1-3 and 7-8), examples (FIG. 4) and/or methods (FIGS. 5-6)
described herein to facilitate wireless communication there
between.
[0068] At base station 910, traffic data for a number of data
streams is provided from a data source 912 to a transmit (TX) data
processor 914. According to an example, each data stream can be
transmitted over a respective antenna. TX data processor 914
formats, codes, and interleaves the traffic data stream based on a
particular coding scheme selected for that data stream to provide
coded data.
[0069] The coded data for each data stream can be multiplexed with
pilot data using orthogonal frequency division multiplexing (OFDM)
techniques. Additionally or alternatively, the pilot symbols can be
frequency division multiplexed (FDM), time division multiplexed
(TDM), or code division multiplexed (CDM). The pilot data is
typically a known data pattern that is processed in a known manner
and can be used at mobile device 950 to estimate channel response.
The multiplexed pilot and coded data for each data stream can be
modulated (e.g., symbol mapped) based on a particular modulation
scheme (e.g., binary phase-shift keying (BPSK), quadrature
phase-shift keying (QPSK), M-phase-shift keying (M-PSK),
M-quadrature amplitude modulation (M-QAM), etc.) selected for that
data stream to provide modulation symbols. The data rate, coding,
and modulation for each data stream can be determined by
instructions performed or provided by processor 930.
[0070] The modulation symbols for the data streams can be provided
to a TX MIMO processor 920, which can further process the
modulation symbols (e.g., for OFDM). TX MIMO processor 920 then
provides N.sub.T modulation symbol streams to N.sub.T transmitters
(TMTR) 922a through 922t. In various embodiments, TX MIMO processor
920 applies beamforming weights to the symbols of the data streams
and to the antenna from which the symbol is being transmitted.
[0071] Each transmitter 922 receives and processes a respective
symbol stream to provide one or more analog signals, and further
conditions (e.g., amplifies, filters, and upconverts) the analog
signals to provide a modulated signal suitable for transmission
over the MIMO channel. Further, N.sub.T modulated signals from
transmitters 922a through 922t are transmitted from N.sub.T
antennas 924a through 924t, respectively.
[0072] At mobile device 950, the transmitted modulated signals are
received by N.sub.R antennas 952a through 952r and the received
signal from each antenna 952 is provided to a respective receiver
(RCVR) 954a through 954r. Each receiver 954 conditions (e.g.,
filters, amplifies, and downconverts) a respective signal,
digitizes the conditioned signal to provide samples, and further
processes the samples to provide a corresponding "received" symbol
stream.
[0073] An RX data processor 960 can receive and process the N.sub.R
received symbol streams from N.sub.R receivers 954 based on a
particular receiver processing technique to provide N.sub.T
"detected" symbol streams. RX data processor 960 can demodulate,
deinterleave, and decode each detected symbol stream to recover the
traffic data for the data stream. The processing by RX data
processor 960 is complementary to that performed by TX MIMO
processor 1720 and TX data processor 914 at base station 910.
[0074] A processor 970 can periodically determine which precoding
matrix to utilize as discussed above. Further, processor 970 can
formulate a reverse link message comprising a matrix index portion
and a rank value portion.
[0075] The reverse link message can comprise various types of
information regarding the communication link and/or the received
data stream. The reverse link message can be processed by a TX data
processor 938, which also receives traffic data for a number of
data streams from a data source 936, modulated by a modulator 980,
conditioned by transmitters 954a through 954r, and transmitted back
to base station 910.
[0076] At base station 910, the modulated signals from mobile
device 950 are received by antennas 924, conditioned by receivers
922, demodulated by a demodulator 940, and processed by a RX data
processor 942 to extract the reverse link message transmitted by
mobile device 950. Further, processor 930 can process the extracted
message to determine which precoding matrix to use for determining
the beamforming weights.
[0077] Processors 930 and 970 can direct (e.g., control,
coordinate, manage, etc.) operation at base station 910 and mobile
device 950, respectively. Respective processors 930 and 970 can be
associated with memory 932 and 972 that store program codes and
data. Processors 930 and 970 can also perform computations to
derive frequency and impulse response estimates for the uplink and
downlink, respectively.
[0078] It is to be understood that the embodiments described herein
can be implemented in hardware, software, firmware, middleware,
microcode, or any combination thereof. For a hardware
implementation, the processing units can be implemented within one
or more application specific integrated circuits (ASICs), digital
signal processors (DSPs), digital signal processing devices
(DSPDs), programmable logic devices (PLDs), field programmable gate
arrays (FPGAs), processors, controllers, micro-controllers,
microprocessors, other electronic units designed to perform the
functions described herein, or a combination thereof.
[0079] When the embodiments are implemented in software, firmware,
middleware or microcode, program code or code segments, they can be
stored in a machine-readable medium, such as a storage component. A
code segment can represent a procedure, a function, a subprogram, a
program, a routine, a subroutine, a module, a software package, a
class, or any combination of instructions, data structures, or
program statements. A code segment can be coupled to another code
segment or a hardware circuit by passing and/or receiving
information, data, arguments, parameters, or memory contents.
Information, arguments, parameters, data, etc. can be passed,
forwarded, or transmitted using any suitable means including memory
sharing, message passing, token passing, network transmission,
etc.
[0080] For a software implementation, the techniques described
herein can be implemented with modules (e.g., procedures,
functions, and so on) that perform the functions described herein.
The software codes can be stored in memory units and executed by
processors. The memory unit can be implemented within the processor
or external to the processor, in which case it can be
communicatively coupled to the processor via various means as is
known in the art.
[0081] With reference to FIG. 10, illustrated is a system 1000 that
determines a header format to employ in transmitting data in a
wireless communication system. For example, system 1000 can reside
at least partially within a base station, mobile device, etc. It is
to be appreciated that system 1000 is represented as including
functional blocks, which can be functional blocks that represent
functions implemented by a processor, software, or combination
thereof (e.g., firmware). System 1000 includes a logical grouping
1002 of electrical components that can act in conjunction. For
instance, logical grouping 1002 can include an electrical component
for determining type of data included in an associated protocol
data unit 1004. Further, logical grouping 1002 can comprise an
electrical component for generating a medium access control header
in accordance with a header format that corresponds to the
determined type of data 1006. Moreover, logical grouping 1002 can
comprise an electrical component for transmitting the medium access
control header and the associated protocol data unit 1008.
Additionally, system 1000 can include a memory 1010 that retains
instructions for executing functions associated with electrical
components 1004, 1006, and 1008. While shown as being external to
memory 1010, it is to be understood that one or more of electrical
components 1004, 1006, and 1008 can exist within memory 1010.
[0082] With reference to FIG. 11, illustrated is a system 1100 that
facilitates receiving transmissions that include variable medium
access control header formats. For example, system 1100 can reside
at least partially within a base station, mobile device, etc. It is
to be appreciated that system 1100 is represented as including
functional blocks, which can be functional blocks that represent
functions implemented by a processor, software, or combination
thereof (e.g., firmware). System 1100 includes a logical grouping
1102 of electrical components that can act in conjunction. For
instance, logical grouping 1102 can include an electrical component
for receiving a medium access control protocol data unit and an
associated header 1104. Further, logical grouping 1102 can comprise
an electrical component for determining a type of data included the
packet data unit based at least in part on a logical channel
identifier in the associated header 1106. Moreover, logical
grouping 1102 can comprise an electrical component for evaluating
the medium access control protocol data unit in accordance with the
type of data and one or more protocol layers 1108. Additionally,
system 1100 can include a memory 1110 that retains instructions for
executing functions associated with electrical components 1104,
1106, and 1108. While shown as being external to memory 1110, it is
to be understood that one or more of electrical components 1104,
1106, and 1108 can exist within memory 1110.
[0083] What has been described above includes examples of one or
more embodiments. It is, of course, not possible to describe every
conceivable combination of components or methodologies for purposes
of describing the aforementioned embodiments, but one of ordinary
skill in the art may recognize that many further combinations and
permutations of various embodiments are possible. Accordingly, the
described embodiments are intended to embrace all such alterations,
modifications and variations that fall within the spirit and scope
of the appended claims. Furthermore, to the extent that the term
"includes" is used in either the detailed description or the
claims, such term is intended to be inclusive in a manner similar
to the term "comprising" as "comprising" is interpreted when
employed as a transitional word in a claim.
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